The present invention relates to a format with an embedded pattern, an apparatus for producing the format, and an apparatus for reproducing the format thus produced. More particularly the invention relates to a format such as a character or letter, a document, a picture, or the like in which a pattern that cannot be differentiated from other formats observed macroscopically but can be differentiated from the other format observed microscopically is embedded. The invention also relates an apparatus for producing such a format with an embedded pattern and to an apparatus for reproducing the format thus produced.
There are generally known permanent and temporary types of information to be recorded in a specified format or form. For instance, the full name, address, registration number, etc. of employees or other personnel can be permanently entered in a salary ledger or attendance record book, but the amount of salary, the amount of tax, attendance or absence, etc. temporarily filled therein and revised from time to time. At the end of each year, the full name, address and the like are manually rewritten in a new salary ledger or new attendance record book, which disadvantageously requires much effort and is attended by a great possibility of error.
To avoid this, a special overlay mask can be used which is formed to conceal the portion to be deleted or revised. The mask is superposed on the desired portion and the format or form is copied using an ordinary copying machine, thereby retaining only the permanent data and deleting or erasing the temporary data, that is, reproducing only the format or form. Although necessary time and labor can be reduced using to this method, a number of different types of overlay masks are required corresponding to the respective formats and matching of the mask to the format requires much effort resulting in a low working efficiency.